body {
  width: 50vw;
  height: 50vh;
  background-color: rgb(75, 75, 220);
  display: flex;
  justify-content: center;
  align-items: center;
}

/* Switch开关样式 */
input[type="checkbox"].switch {
  outline: none;
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
  position: relative;
  width: 40px;
  height: 20px;
  background: #ccc;
  border-radius: 10px;
  transition: border-color 0.3s, background-color 0.3s;
}

input[type="checkbox"].switch::after {
  content: "";
  display: inline-block;
  width: 1rem;
  height: 1rem;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0, 0, 2px, #999;
  transition: 0.4s;
  top: 2px;
  position: absolute;
  left: 2px;
}

input[type="checkbox"].switch:checked {
  background: rgb(19, 206, 102);
}

/* 当input[type=checkbox]被选中时：伪元素显示下面样式 位置发生变化 */
input[type="checkbox"].switch:checked::after {
  content: "";
  position: absolute;
  left: 55%;
  top: 2px;
}
